No Internet Connection after Installing Norton 360

My dad recently upgrade my mom's computer from Norton Internet Security to Norton 360. The installation and setup FORCE the customer to uninstall Windows Defender. I followed all the steps, and the last connection to the Internet was when Norton 360 downloaded Live Update. After the computer rebooted, I could NOT activate Norton 360 and there was no connection to the Internet. I even tried turning off the Norton product for 15 minutes, but no go. Finally, I uninstalled Norton 360 so I can get on the Internet. What is the solution to this problem so I can get Norton 360 Installed, set up, activated, and go about my business online?